The present invention relates to removal of microorganisms capable of multiplying in water retained in a humidifier (microorganism removal). More specifically, it relates to a humidifier capable of removing microorganism from water in a reservoir, sucking water after the microorganism removal into a humidification filter and discharging air humidified through the humidification filter.
In a conventional humidifier, outside air is inhaled and water in the humidifier is vaporized to discharge the inhaled air together with the vapor outside the humidifier. In the water retained in the humidifier, is observed multiplication of microorganisms such as bacteria including E. coli and S. aureus. As for an ultrasonic humidifier from which water atomized by ultrasonic waves is discharged, the microorganisms grown in the retained water may possibly be discharged alive. The humidifier also has a side effect of cooling the air.
On the other hand, a heating humidifier discharges high temperature vapor from a built-in boiler. Accordingly, even if the microorganisms are multiplied while the humidifier is out of service, they are sterilized by heat and hence the possibility of discharging the microorganisms alive is low. Such a humidifier has been designed not to discharge dead microorganisms in the air, but has a problem of high power consumption of the heater.
In contrast to these, there is a so-called hybrid humidifier in which water is sucked up to a humidification filter and air humidified through the humidification filter is discharged. However, also in this humidifier, the microorganisms are multiplied in the retained water while the humidifier is left unoperated. If the humidifier is left for an extremely long time, the multiplication of the microorganisms may be accompanied with a rot odor. On this account, there has been longed for a technique of inhibiting the microorganism multiplication in the humidifier and removing the microorganism.
For example, Japanese Laid-Open Patent Publication No. 2002-12239 proposes a hybrid humidifier as shown in FIGS. 16 to 18. FIG. 16 is a schematic perspective view of the prior art humidifier, FIG. 17 is a schematic perspective view illustrating an inner structure of the humidifier of FIG. 16 and FIG. 18 is another schematic perspective view illustrating the inner structure of the humidifier of FIG. 16.
This humidifier includes an inlet opening 100a and an outlet opening 100b opened in the main body or a cover. The main body contains therein a reservoir 102 for receiving water supplied from a water reservation tank 101, a heating tube 103 for heating water in the reservoir 102 and a water absorber 104 (humidification filter) surrounding the heating tube 103 to suck up the water in the reservoir 102. Further, an air path is formed from the inlet opening 100a through a blower 105 to the outlet opening 100b. Air introduced from the inlet opening 100a is discharged by the blower 105 together with a vapor generated from the water absorber 104 out of the outlet opening 100b. Thus, the room air is humidified.
Water in the water reservation tank 101 is supplied to the reservoir 102. The reservoir 102 includes, somewhere in the inside thereof, a pair of electrodes 107 which releases an antimicrobial substance. A degree of humidification is varied by passing electricity between the electrodes and changing the polarities at a predetermined cycle. However, in the prior art humidifier, carrying electricity to the electrodes 107 needs to be controlled to inhibit the microorganism multiplication, which complicates the humidifier and increases power consumption.
On the other hand, as a means of inhibiting the microorganism multiplication, irradiation of ultraviolet rays and intermittent heating have been proposed. However, while the humidifier is left unoperated, power supply is stopped in many cases and hence these means are relatively difficult to adopt in a practical sense. From this point of view, there is demanded for a humidifier capable of inhibiting the microorganism multiplication and disinfecting the bacteria with use of a small power generated by a storage power source, without using an external power source.
As described in Japanese Laid-Open Patent Publication No. HEI 4-335934, it is also conceivable to prevent the microorganism multiplication by adding or applying an antimicrobial substance to the components of the humidifier. In this case, however, the antimicrobial effect is insufficient because it is exerted only on the surface of the components, which results in a low degree of prevention of the microorganism multiplication in water retained or flowing in the humidifier.
International Publication WO 00/77163 A1 discloses a technique of removing protein-coated particles by moving them between the electrodes without using the external power source. This technique is considered as a solution to the problems involved with the conventional humidifiers.